Non-Patent Document 1 proposes technology known as OpenFlow. OpenFlow treats communication as end-to-end flow, and performs path control, malfunction recovery, load balancing, and optimization, in flow units. An OpenFlow switch is provided with a secure channel for communication with an OpenFlow controller, and operates in accordance with a flow table for which appropriate adding or rewriting is instructed by the OpenFlow controller. The flow table records flow entries formed of a set of rules that refer to a packet header, actions that define processing content, and flow statistical formation, for each of a plurality of flows.
For example, when the OpenFlow switch receives a first packet, a search is made for an entry Wow entry) having a rule (Flow Key) that matches header information of the received packet, from the flow table. In a case where, as a result of the search, a flow entry matching the received packet is found, the OpenFlow switch implements processing content described in an action field of the flow entry, with regard to the received packet. On the other hand, in a case where, as a result of the search, a flow entry matching a received packet is not found, the OpenFlow switch forwards the received packet to the OpenFlow controller, via the secure channel, requests a determination of a packet path based on a source and destination of the received packet, receives a flow entry realizing this, and updates the flow table.
Furthermore, although not directly related to the abovementioned OpenFlow, Patent Documents 1 and 2 below were detected and thus are mentioned.
Patent Document 1 discloses a home agent of a mobile communication system based on mobile IP, having an interface means for routing a received packet in accordance with a forwarding table, and a location information management means for managing the forwarding table. The forwarding table held by the home agent in the same document includes at least relationships of association for port numbers distinguishing global IP addresses (HoA) for mobile nodes, and care-of addresses (CoA) for mobile nodes, and applications, and a forwarding destination of a packet received by the home agent is differentiated by a combination of the CoA and port number. In the document, each of a plurality of mobile nodes is configured to detect when one or more of the HoA, CoA, and port number of the node itself has changed, and to report to the home agent.
Patent Document 2 discloses a packet buffer device that uses a flow table to perform weighted fair queuing among flows.
[Patent Document 1]
    Japanese Patent Kokai Publication No. JP 008-067055A[Patent Document 2]    Japanese Patent Kokai Publication No. JP-A-09-149051[Non-Patent Document 1]    Nick McKeown, and 7 others, “OpenFlow: Enabling Innovation in Campus Networks”, [online], [search conducted Oct. 15, 2009]    Internet URL: http://www.OpenFlowswitch.org//documents/OpenFlow-wp-latest.pdf